哪个地方产的钻石质量最好?

 　　zaihenduorendeyishizhong，nanfeizuanshishishijieshangzuihaodezuanshi，maizuanshifeinanfeizuanbumai，zheizhongxiangfazhendezhengquema?nanfeizuanshizhendeshishijieshangzuihaodezuanshima?zuanshichandijuedingzuanshipinzhima?

　　nanfeizuanshizhisuoyichuming，jinjinyinweizaigaiguozuizaofaxianledaxingzuanshiyuanshengkuang。suiranzuanshideyuanchandidaduoshinanfei，danshichandizainalibingbunengquedingsuoxuandejiuyidingshihaozuanshi，yinweigoumaizuanshishikan4cbiaozhun，erfeizhikanchandi，chandizhishuoshiyigewuqu。nanfeizhishizuanshichanliangzuiduodeguojia，bunengshuonanfeidezuanshijiushizuihaode，renhekuangquchanchudezuanshidouyouhao、zhong、chadengjizhifen。shijiegedijunyouzuanshichanchu，shijieshangyousanshiduogeguojiadouyongyouzuanshiziyuan，meinianzuanshidechanliangzaiyiyikelazuoyou。chanliangzaiqianwuweideguojiashiaodaliya、zhayier、bociwana、eluosi、nanfei，zheiwugeguojiadezuanshichanliangzhanquanshijiezuanshichanliangde90%zuoyou。

　　hengliangyikezuanshipinzhidebiaozhunzhuyaoyousige，jizhongliang(carat)、jingdu(clarity)、seze(colour)heqiegong(cut)，yejiushitongchangsuoshuode“4cbiaozhun”。zheigebiaozhunyougia(meiguobaoshixueyuan)chuangli，shimuqianzaishijieshangbaokuozhongguozuiweizhuliudezuanshipingjiabiaozhun。

　　zuanshiyouguojirenkedebaoshixuejiajinxingjiandingbingqianfadisanfangdulideyijianshu，jiyu4cbiaozhun，jierjuedingzuanshijiage。nagedifangchandezuanshizhiliangzuihao?zuanshidezhiliangyuqichanpinmeiyoubirandelianxi，zuanshidezhiliangbingbunengyichandilaipingpan，haozhiliangdezuanshishiyouqi4cbiaozhunjuedingde。